Suggest to install KDE 4.9.3+ for the KDE compositing fix

~/kde-workspace$ git log v4.9.3 | grep 55a2f19c8a41d9b3d13d69d7769999daf5730414
commit 55a2f19c8a41d9b3d13d69d7769999daf5730414
~/kde-workspace$ git log v4.9.2 | grep 55a2f19c8a41d9b3d13d69d7769999daf5730414
<empty>
55a2f19c8a41d9b3d13d69d7769999daf5730414 is the KDE 4.9 backport of 20e6349843d9bb838673a301330d7dc5d08401a5, which is the commit/fix you linked to.